To a stirred solution of 3-amino-4-phenylamino-benzoic acid (prepared from 3-nitro-4-phenylamino-benzoic acid as described in the general procedure, 2.04 gm, 8.94 mmol) in THF (25 mL) was added carbonyl diimidazole (3.62 gm, 22.34 mmol). After stirring for 1 hour at room temperature, N,O-dimethylhydroxyl amine (1.31 gm, 13.41 mmol) was added in one portion. Stirring was continued at room temperature for an additional 2 hours after which time the reaction was determined to be complete by LC-MS. The THF was removed in vacuo and the residue was diluted with water and extracted with methylene chloride three times. The combined methylene chloride extracts were dried over anhydrous sodium sulfate and concentrated in vacuo to afford 2.23 gm of the title compound as a tan solid which was used without further purification.
